A. Ellenstein, an MD/PHD student at BUSM, received training in gas chromatography/mass spectrometry using the Finnigan/Thermo BioQuest GC-Q ion trap mass spectrometer. She became proficient in operating the instrument in its primary full-scan mode, as well as in the multiple-ion monitoring and other specialized modes available for tandem mass spectral measurements. She also learned techniques for microscale sample preparation and derivatization and approaches for interpretation of mass spectra. Her project was part of a summer training program organized to give students who have completed their first year of the MD/PhD program an opportunity to perform basic research. In the analysis, the transfer of cannabinoids from mother to child was monitored through examination of meconium.